Identify an equation in point-slope form for the line perpendicular to y=-4x-1 that passes through (-2,7)

Question

asked Apr 13, 2019 151k views

1 Answer

Salhin · Answer 1 · 2019-04-16T21:09:01+0000

I find it simplest to convert to standard form, find the perpendicular, convert back.

y = -4x - 1

For standard form we move the x term to the left side:

4x + y = -1

The perpendiculars are given by swapping the x and y coefficients, negating one. The right side is directly determined by the point (-2,7):

x - 4y = -2 - 4(7) = -30

Solve for y for point slope form:

4y = x + 30

$y = \frac 1 4 x + (15)/(2)$

That's the answer.